Gustav henry block



to obtain a sharp transfer.

UNITED STATES PATENT OFFICE.

GUSTAV HENRY BLOCK, OF LONDON, ENGLAND PREPARATION OF SURFACES FORPLANOGRAPHIC PRINTING.

SPECIFICATION forming part of Letters Patent No. 622,879, dated April11, 1899.

Application filed March 15, 1894. Serial No. 503,783- (No specimens.)

To (0U whom it may concern:

- Be it known that I, GUSTAV HENRY BLooK',

a subject of the Queen of Great Britain, residing at London, England,have invented new and useful Improvements in the Preparation of Surfacesfor Lithographic and other Printing, (for which I have secured LettersPatent in the following countries, to wit;

France, No. 236,912, dated March 10, 1894; Belgium, No. 108,967, datedMarch 10, 1894; Italy, XXVIII, 25,907, LXX, 298, dated March 31, 1894;Canada, No. 46,042, dated May 14, 1894; Austria, No. 44/2,187, datedJune 5, 1894; Germany, No. 84,231, dated March 11, 1894, and GreatBritain, No. 2,907,dat.ed February 9, 1894;) and I do hereby declarethat the following is a full, clear, and exact description of theinvention, which will enable others skilled in the art to which itappertains to make and use the same.

My invention relates to the preparation of lithographic and otherprinting surfaces, and has for its object to produce on lithographicstones and zinc and other metal plates stippled or lined surfaces moreeconomicallyand expeditiously than heretofore.

According to my invention the surface to be prepared (whether metal orlithographic stone) is firstcleaned in the usual manner and then thelinework or stipple-work is transferred to the surface in the usualmanner,

either by lithography, photolithography, or otherwise from apreviously-prepared or permanent original.

In practice I prefer to pull a transfer of the stipple-work from anexisting original, using a transfer-ink of a strong consistency, so asIf the transfer is pulled too full with too much ink, the stipple-workwill not transfer to the surface so sharp and even as is necessary, andwhen such transfer is inked up in the ordinary lithographic manner witha black litho-roller the stipple-work will lose its sharpness.

. The stipple transfer-sheet is placed in a damping-book and whensufiiciently damp is laid face downward on the previously-cleanedsurface to be treated and pulled several times through a lithographicpress. The transfer-paper is then damped and soaked ofi of the surfaceunder treatment, leaving the transfer-ink on the said surface. Afterthis operation the surface is gummed up with a solution of gum-arabicwhich is left to dry on. This .gum ming up is of a great consequence tothe rolling-up process. The gum solution acts as a weak acid on theunprotected parts between the stipple-work. Further, the dried gumsolution deposits a film which does not dissolve readily in cold water.These are mainly the reasons that tlie surface does not roll up solidblack, but inks up only the stipple work when the transfer is rolled up,as described farther on. Then the stipple-trausfer on said surface isrolled up with an acid-proof composition, preferablya good fattylithographic ink, which contains a small amount of beeswax, gum-damar,and asphalt previously dissolved in turpentine. To roll up the transfer,the surface is first dampened with a water-sponge and damping-cloth toenable the moisture to penetrate between the stipple-work of thetransfer. So when rolling up with the greasy acid-proof ink the rollerinks up only the stipple deposited from the transfer-paper and doesnotink the whole sur face of the plate, providing the surface is keptmoist while the rolling-up process is carried on. The surface is thenetched to the desired depth with an acid, so as to leave thestipple-work in relief and of the necessary height. Then the etching iscompleted, the surface is treated with an alkaline solution to removethe acid-proof composition and destroy'the grease which remains on theplate from the original transfer and the acid-proof composition. Thisdestruction of all the greasy matters which are on or in the surface ofthe plate is a very important step in my process. It is not sufficientto wash out the stipple-work pattern with turpentine, for this does notremove and destroy all the grease.

By using my alkaline solution the grease may be entirely removed, andthis step must be very thoroughly and carefully performed, for if thegrease is not destroyed from the raised surface the stipple-work wouldwork up again when printing, the design would be obliterated, and thework done by the artist would be lost. After a planographic surfacetherein.

cleaned from grease, as above described, it is sensitized, so as torender the surface fit for use for lithographic purposes withoutapplying a coating in such laborious manner as used heretofore.

The plate is placed in a bath composed of nitric acid, alum, and water,in the proportion of, say, nitric acid one quart, alum three pounds, andwater fifty quarts, for the purpose of oxidizing the surface of theplate, the bath being shaken all the time the plate remains WVhen theplate has been in this bath for about one-half aminute, it is taken outand rinsed with water and all the loose oxid which has formed is removedby rubbing with a sponge or flannel. The plate is then again placed inthe bath and left therein un-. til oXid ceases to form thereon, (thebath is kept in motion also during the second insertion,) whereupon theplate is removed and cleaned from the loose oxid, as described before,these operations causing, through the action of the acid and alum on theprevious flat relief stipple-tops, a slightly roughened and crystallinecondition and produce a good grip for the lithographic crayon Thesurface of the plate is finally rubbed over with carbonate of magnesiaand Water (in the shape of a paste) to'neutralize any acid and removeany loose oxid which may adhere in the lower parts in between thestipple-relief surface. After, the surface of the plate being rinsedwell with water and dried,the surface is ready for the artist ordraftsman, who by using a lithographic crayon can produce designs thelines of which are interrupted or broken according to the nature of theground, thereby producing a combined chalk and stipple effeet.

I may in some instances prepare smooth zinc or other metal plates forlithographic or other printing without an etched stipple relief on thesurface. The surface of the metal plate is first cleaned in the usualmanner. The plate thus cleaned is placed in a bath of solution of nitricacid, alum, and water in the same proportion as described forsensitizing the relief-surface. The object of the treatment is tooxidize the surface of the plate. When the plate has been immersed inthis bath of one-half a minute, (during which time the bath is shaken orkept in motion,) the plate is taken out and rinsed with clean water andrubbed over with a sponge or flannel to remove the loose oxid which isformed. The plate is now again placed in the bath and treated in thesame manner as described be fore. Through this treatment in the bath thenitric acid and alum have a double elfect first, that of unevenly eatingaway the surface of the metal so as to leave itin a slightly roughenedand crystalline condition, which gives the surface a slight grain, whichis essential for lithographic purposes, and, secondly, sen sitizing theplate-surface. The plate-surface is finally rubbed over with carbonateof magnesia to neutralize any acid which may remain thereon and toremove any particles of loose oXid which may cling in the minute poresof the roughened surface.

The plate when rinsed with water and dried is ready for any transferwork or pen-and-ink drawings, 850., and can be used to a great advantageas a substitute for a polished lithostone.

Litho-stones with stipple relief can also be sensitized with the samematerial as used for zinc or metal plates; but as a cumbersome heavylitho-stone could not be placed easily in a bath the sensitizing wouldbe performed by brushing the solution of alum, acetic acid, and waterover the surface of the litho-stone and thereafter rinsing with water.Nitric acid may, however, be employed as an equivalent for the aceticacid. This operation may be repeated several times, so as .to remove anyalkaline solution which the porous lithostone may have absorbed. Finallythe stone surface is rubbed over with carbonate of magnesia toneutralize any acid which may be left between the stipple relief.Further, the carbonate of magnesia abstracts any acid which may haveentered the porous litho-stone.

WVhat I claim, and desire to secure by Letters Patent, is

1. The herein-described process of preparing planographic surfaces,which consists in transferring the stipple-work thereto, rolling up thestipple-work with an acid-proof composition, etching the surface with anacid to leave the stipple-work in relief, treating the surface with analkaline solution to remove the grease and then sensitizing the surface,substantially as described.

2. The herein-described process of preparing planographic surfaces whichconsists in transferring the stipple-work thereto, rolling up thestipple-work with an acid-proof composition, etching the plate with anacid to leave the stipple-work in relief, treating the surface with analkaline solution to remove the grease, sensitizing the surface bytreating itwith a bath of an acid and alum, and then treating thesurface with carbonate of magnesium, substantially as described.

3. The herein-described process of preparing a planographic plate whichconsists in treating it with a bath of an acid andalum,

IIO

and then treating it with carbonate of magne sium, substantially asdescribed. I

4. The herein-described process of preparing a planographic plate whichconsists in treating it with a bath of nitric acid and alum, and thentreating it with carbonate of magnesium, substantially as described.

GUSTAV HENRY BLOCK.

Witnesses; G. F. REDFERN,

JOHN E. BoUsFIELD.

